Barcelona's offside trap has been a key feature of the team's play this season under new manager Hansi Flick.
The Catalans are playing an aggressively high line which has seen the offside count stack up so far this season. Barca have caught opponents offside 107 times this season - that's twice as many as any other team in Europe's top five leagues.
Flick has hailed his team's ability to carry out his instructions, while defenders Pau Cubarsi and Inigo Martinez have also praised the system.
Except it all changed on Saturday against Betis. Barca did not catch the hosts offside at all during the 90 minutes. That's zero, zip, zilch.
Unsurprisingly this is the first time it's happened in Barcelona's 22 games in all competitions of far this season and will hand Flick plenty to ponder ahead of games against Dortmund and Atletico.